CVE-2022-50355 in Linux
Summary
by MITRE • 09/17/2025
In the Linux kernel, the following vulnerability has been resolved:
staging: vt6655: fix some erroneous memory clean-up loops
In some initialization functions of this driver, memory is allocated with 'i' acting as an index variable and increasing from 0. The commit in "Fixes" introduces some clean-up codes in case of allocation failure, which free memory in reverse order with 'i' decreasing to 0. However, there are some problems: - The case i=0 is left out. Thus memory is leaked. - In case memory allocation fails right from the start, the memory freeing loops will start with i=-1 and invalid memory locations will be accessed.
One of these loops has been fixed in commit c8ff91535880 ("staging: vt6655: fix potential memory leak"). Fix the remaining erroneous loops.
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Analysis
by VulDB Data Team • 12/23/2025
The vulnerability identified as CVE-2022-50355 resides within the Linux kernel's staging driver for the vt6655 wireless network adapter. This issue represents a classic memory management flaw that occurs during driver initialization phases, where improper loop indexing leads to both memory leaks and potential kernel crashes. The vt6655 driver is part of the Linux kernel's staging area, indicating it's a driver that has not yet reached full kernel integration status and may contain incomplete or unoptimized code. The vulnerability specifically affects the driver's initialization functions where memory allocation occurs using an index variable 'i' that increments from zero. When allocation failures occur, the driver attempts to clean up previously allocated memory by iterating in reverse order with the same index variable decrementing back to zero.
The technical flaw manifests in two distinct but related issues that compound the memory management error. First, when the cleanup loop executes, it omits the case where i equals zero, meaning the final allocated memory segment is never freed, resulting in a memory leak that persists until the driver is unloaded or the system reboots. Second, in scenarios where allocation fails immediately during the first iteration, the cleanup loop begins with i set to negative one, causing the driver to attempt freeing memory from invalid memory addresses. This second condition can lead to kernel panics or undefined behavior as the driver accesses memory locations that were never allocated or are outside the valid memory boundaries. The vulnerability is classified under CWE-459, which describes "Incomplete Cleanup" and falls within the broader category of memory management errors that can lead to resource exhaustion and system instability.
The operational impact of this vulnerability extends beyond simple memory leaks to potentially compromise system stability and security. Memory leaks in kernel drivers can gradually consume system resources, leading to performance degradation or system crashes under sustained load conditions. When combined with the invalid memory access scenario, the vulnerability presents a potential attack vector that could be exploited to cause denial of service or, in more sophisticated scenarios, potentially lead to privilege escalation. The staging nature of this driver means that it's not subject to the same level of code review and testing as fully integrated kernel components, making such flaws more likely to persist. The vulnerability affects systems running Linux kernels that include the vt6655 driver, particularly those with wireless network capabilities using this specific chipset, and represents a risk to any system where the driver is loaded or activated.
Mitigation strategies for CVE-2022-50355 focus on both immediate patch application and system hardening approaches. The primary fix involves correcting the memory cleanup loops to properly handle all index values including zero and to prevent negative indexing scenarios during cleanup operations. System administrators should ensure their kernel versions include the patched vt6655 driver code, which was addressed in commit c8ff91535880 and subsequently corrected for the remaining loops. For systems where immediate kernel updates are not feasible, administrators can disable the vt6655 driver module through kernel configuration or by preventing automatic loading of the module. The vulnerability aligns with ATT&CK technique T1068, which involves exploiting local privileges to gain system-level access through kernel vulnerabilities. Organizations should monitor their kernel versions and apply security patches promptly, particularly in environments where wireless networking is utilized. Additionally, implementing proper memory debugging tools and kernel memory sanitizers can help detect similar issues in other drivers, as the underlying problem pattern of improper loop indexing and cleanup operations is common across various kernel subsystems and can manifest in other drivers as well.